Who makes an AR hammer that has more weight to it than most?

Not the hammer spring; I'm speaking of the hammer itself.

I Googled and Googled but all I got was my wife saying "stop Googling so much...you'll go blind"

Thanks,

G.

I have never heard of that. only less mass is being looked for normally.
what issue are you trying to solve for with a hammer with more mass?

you could add it yourself, like putting tungston or some inserts?

look into the folks that sell .50 bmg uppers, jard i believe sells a heavier than normal hammer and springs.

May I ask why and potential application?

I think tungsten weights might be the easiest solution.

I like the strike a heavy hammer gives in my LR308 type builds. This is simply a personal preference.

Finding heavier (stronger) hammer springs is easy. Finding a heavier hammer, not so much.

As counter intuitive as it sounds i thought lighter hammers give a harder hammer strike because of the increased lock speed.  I could be all wet on this.  

If you lighten the springs you may (I did) need to lighten the hammer to increase the hammer speed to make up for the loss in mass.  Heavy hammer needs heavy spring to get it to hit as hard as light hammer + light springs.   It's a mass over velocity versus fixed length of rotation issue.   Heavy hammer hits harder based on mass while lighter hammer hits harder based on velocity.  

Light hammer + light spring has a arguable benefit of a increased lock speed although it's on the order of milliseconds.  But for some the possibility in decreasing the amount of time the human factor has to mess up the shot between the point the trigger breaks and the hammer hits is worth investigating.

The most common reason to lighten springs and the one I had is to get a lighter stock milspec trigger.   Swapping from stock to yellow springs dropped me from a 6.5lb trigger to a 4lb trigger.  But I I ended up having to bob the hammer to speed it up a bit to get back to 100% reliability with milspec ammo.  

A heavier hammer will require heavier springs and result in a heavier trigger pull using the standard milspec FCG but there's nothing inherently wrong with it.  I've not personally seen hammers billed as heavier than milspec but there's probably someone somewhere doing it.

The heavier hammer also has an effect on the recoiling bolt carrier group.

It's not a big effect I know, but using a heavier hammer can add to the reliability of a particular build. Not every rifle needs or benefits from a heavier hammer, but some do.

I have a build I want the heavier hammer for.

When all you have is a heavier hammer, the whole world looks like a titanium nail.

G.

It depends on the design.  Lighter hammers must travel faster to generate equal impact energy.  That's easy math.  Where things get more complicated is when you start dealing with firing pins.  Heavier hammers at lower velocity generating equal impact energy as their lighter/faster counterparts have greater momentum to overcome heavy firing pins or firing pin springs.  But you still need sufficient velocity to ignite the primer; there is a balance.

So, in some designs, a heavy hammer works better.  In others, a light/fast hammer is key.

Agreed, however "sometimes" that lighter hammer / spring combo can give one miss fires due to light strike on the primer. I'm running a JP low mass H/T/S for some time. I "discovered" the light H & spring was causing some light primer hits. Enough i ended up switching back to the stock hammer spring.
Unfortunately there is no perfect combo (as in general consensus) one would suggest. AS each combo may function  (like reloaded ammo in different barrels) differently for ones need.
I use the JP, Have the ALG/QMS and soon a G2S? to try out. Each used in different applications. YMMV

Hiperfire EDT2

Same as the EDT but with a heavier hammer for hard primers.  They claim faster lock times than milspec stock even with the heavier hammer.

Franklin Armory's binary trigger has the largest hammer I've seen in an AR.

I think hiperfire will give you the highest impact energy of any available AR trigger.